ER32 Collet Chuck for Proxxon PD 400

[Wongster]

Envy envy envy... I only get to pour water into the sink....

[Wongster]

Another short session today of about an hour to an hour and a half. The nose is now down to slightly below 50mm in diameter after "smoothening" out the surface. The spindle was bumped up to 660 rpm with very light cut using the Sherline's carbide insert tool. The tip on this tool has radius of 0.4mm. The result was great! The flange was also squared up and finished with the same method. I realised that I've to lock down the carriage to produce a decent finish when face turning. Also, I discovered that having a small relief angle between the edge of the insert and the work helps in the finish.

Facing the flange



The surfaces are rather smooth to touch, despite the looks. I didn't bother to sand down the surface.



From another angle. Should have also smoothen out the face of the nose, just for the fun of it.



Flipping it around in the 3 jaw chuck. I wanted to see if the jaws give enough clearance for drilling and boring the centre hole. Changed my mind doing the bore at this stage.



I left slightly smaller than 50mm in diameter on the nose after discussing this with GeneK. The idea is to finished up the recess and mounting holes first, mount it on the spindle flange, and turn the nose true to the setup. I'm hoping that I've left enough "meat" for the purpose.

Wanted to make the gauge Dave pointed out but the biggest piece of aluminium stock is a tad too small and I'm not prepared to turn down a piece of rectangular aluminium stock for this. I'll be visiting the metal shop, hopefully this coming week, to buy the required. At the same time, will be getting a thicker piece of mild steel stock to make this chuck as the material left for the flange seems a bit on the thin side.

Few questions:
1) Should I be boring the centre hole and turn the taper before threading?
2) On the mounting holes, I was planning to follow the article posted on the 7x12minilathe to mark the hole positions till I saw an article on Tool and Mods http://www.toolsandmods.com/mini-lathe-c...plate.html The author scribed the PCD of the mounting holes on the lathe after indexing the tool to the centre line. I don't really understand how he did the indexing and dropped him an email yesterday, hoping that he will reply. Any other methods available to do this?
3) On the mounting holes again, should I go with 3 holes or 4?

Regards,
Wong

[DaveH]

(05-13-2012, 12:13 AM)Wongster Wrote: Few questions:
1) Should I be boring the centre hole and turn the taper before threading?
2) On the mounting holes, I was planning to follow the article posted on the 7x12minilathe to mark the hole positions till I saw an article on Tool and Mods http://www.toolsandmods.com/mini-lathe-c...plate.html The author scribed the PCD of the mounting holes on the lathe after indexing the tool to the centre line. I don't really understand how he did the indexing and dropped him an email yesterday, hoping that he will reply. Any other methods available to do this?
3) On the mounting holes again, should I go with 3 holes or 4?

Regards,
Wong

1) Whatever you fancy

2) It is much easier to scribe the PCD with a pair of scribers but you need a centre so don't drill a hole until the scribed PCD is done. Mark the 6 points on the PCD line using the scribers set to the PCD radius, and just use 3 @ 120 deg apart.

3) 3 holes is just fine The holes are for screws to hold your ER 32 chuck on to the back plate - that's all they do, they do not locate it.

Looking good Wong

DaveH

[DaveH]

Wong,
To scribe the PCD you need the centre, this is made by a small centre drill or small spotting drill. This can be done on your lathe.

DaveH

[Wongster]

Dave,

How do I centre the tool/scriber in the tool post do that I can move the cross slide to scribe the circle for the mounting holes? To index for the 3 hole positions, will the 3 jaws if the chuck be sufficient to act as positional stops? I don't have any means to index the spindle.

Regards,
Wong

[DaveH]

(05-13-2012, 08:00 AM)Wongster Wrote: Dave,

How do I centre the tool/scriber in the tool post do that I can move the cross slide to scribe the circle for the mounting holes? To index for the 3 hole positions, will the 3 jaws if the chuck be sufficient to act as positional stops? I don't have any means to index the spindle.

Regards,
Wong

Hi Wong,
May be I am using the wrong words -pair of scriber's. Their real name is dividers, much like a pair of compass - only both ends have a point

Sorry Wong may have confused you a little here, so there is no need to index on the lathe or to put a scriber in the tool post.

Use the divider's as you would a pair of compass


DaveH

[Wongster]

Dave,

I suspected that you mean the divider. Wouldn't the hole from the centre drill too rounded to accurately hold the pointy end of the divider? I've this:



Picked it up used. Will using the divider gives the required accuracy to match up with the exacting taped holes on the spindle flange?

Regards,
Wong

[DaveH]

Hi Wong,

Before any marking first face it

As for the centre, if you wish you can just have something in the tail stock to mark it and then centre punch it lightly. Just to stop the point on the divider slipping

As long as you know what the PCD is, the hole(s) accuracy will be fine. Just be careful when you mark it and use the centre punch

And if I remember correctly these will be clearance holes.

DaveH

[Wongster]

Dave,

I'll start facing and cleaning up the "other side" once I've the recess gauge made. I'll then scribe the circle and do up the recess.

Yes, you remember right, they're clearance holes.

Regards,
Wong

[Wongster]

I made a quick trip down to the metal shop today to grab a piece of aluminium for the recess gauge. It turned out to be a mistake... Should have checked before I leave the shop. I asked for around 75 to 80mm diameter and didn't realize that the shop assistant wrapped up a piece of 120mm diameter piece! Only found out when I got home... sigh... another trip needed but tomorrow is a busy day...